I found this information on PCWorld's web site. I don't know if this has been posted before but I thought I would share it.

"Slacker has signed a partnership with Research in Motion to offer a personal radio application free of charge to all BlackBerry phones running OS 4.3 or later. The app will let users link up live to any Slacker station, any time. The only restriction is that you can only skip tracks six times per hour. And fear not: The service will stay ad-free until at least next year, RIM says."